The purpose of this shared instrumentation grant is to obtain funds to purchase freeze-etch and rotary shadowing instrumentation to be used principally by a group of investigators in the Department of Molecular Biology at the Research Institute of Scripps Clinic. The Department of Molecular Biology is a new Department which has recently expanded into the area of cell biology. With this new addition to the Department, there is a significant need for contemporary electron microscopic instrumentation. The Department currently has 43 full-time faculty members, and the present proposal represents a collective need for the proposed shared instrumentation by 8 of these members. The Balzers Freeze-Etch Unit and the Edwards Rotary Shadowing device have been selected by the members of the internal Advisory Committee. This instrumentation was selected by the internal Advisory Committee on the basis of their prior experience with this instrumentation and its capability for performing the various activities that will be required by this diverse set of users.